| 其他書名 | Recommended by the Second Conference of State Highway Testing Engineers and Chemists, Washington, D.C., Feb. 23-27, 1920 |
| 出版 | U.S. Department of Agriculture, 1922 |
| URL | http://books.google.com.hk/books?id=DM7BaQdpSuIC&hl=&source=gbs_api |
| EBook | FULL_PUBLIC_DOMAIN |